The invaluable SCOTUS Blog has a long series taking a detailed look at Sotomayor's actual rulings on matters before the Federal and Appeals courts on which she has served.
Here's a rundown of her opinions in civil cases.
Since joining the Second Circuit in 1998, Sotomayor has authored over 150 opinions, addressing a wide range of issues, in civil cases. To date, two of these decisions have been overturned by the Supreme Court; a third is under review and likely to be reversed. In those two cases (and likely the third), Sotomayor’s opinion was rejected by the Supreme Court’s more conservative majority and adopted by its more liberal dissenters (including Justice Souter). Those outcomes suggest that Sotomayor’s views would in many respects be similar to those of Justice Souter.
Here's lots more on a wide range of cases.